MANUFACTURE OF SEMICONDUCTOR SUBSTRATE

• Main Author: ARIMOTO YOSHIHIRO
• Format: Patent
• Language: English
• Published: 07.05.1988
• Subjects: BASIC ELECTRIC ELEMENTS; ELECTRIC SOLID STATE DEVICES NOT OTHERWISE PROVIDED FOR; ELECTRICITY; SEMICONDUCTOR DEVICES

PURPOSE:To obtain an SOI thin film substrate of excellent crystallinity, by forming, on a first silicon substrate, an silicon layer having resistivity higher than the substrate by epitaxial growth, sticking the silicon layer on a second substrate via a silicon oxide layer, and eliminating the first substrate by electrolyte etching. CONSTITUTION:On an N-type Si substrate 1 whose resistivity is about 0.1-0.01OMEGAcm, a P-type Si active layer 5 whose resistivity is about 5-10OMEGAcm is grown by vapor growth applying monosilane (SiH4) as a raw material. On the surface of the Si active layer 5, an SiO2 layer 3 about 0.2mum thick is formed by, for example, steam oxidation. On the surface of an Si substrate 2 whose back surface resistivity is about 0.1OMEGAcm, an SiO2 layer 4 about 0.5mum thick is formed. The Si substrate 1 is lapped thereon, in the manner in which its front surface faces downward, and the SiO2 layer 3 and the SiO2 layer 4 are heated and stuck in an oxidizing atmosphere. Then a substrate 8 after sticking is dipped in an aqueous solution of 2.5% HF (electrolytic solution) 10, and the N-type Si substrate 1 of about 0.1-0.01OMEGAcm is eliminated by electrolytic etching. Then an active layer whose thickness is uniform and less than or equal to 1mum is stably obtained.